1. Field of the Invention
The present invention relates to digital radiography and, more specifically, to a method for the detection of collimator blades in digital radiography images.
2. Description of the Related Art
An essential step in processing digital radiography images is to detect the collimator blades. The information obtained from the detection of the collimator blades is then used to determine the area enclosed by the blades, and the statistics associated with the image within this area are calculated for use in subsequent image processing steps. The portion of image that is outside the area of the collimator blades may then be discarded to facilitate only useful image data storage, transmission and processing.
This technique of identifying the target area and discarded undesired areas is commonly referred to as the Auto Shutter process. The area enclosed by the collimator blades is referred to as the shutter area. The typical Auto Shutter process comprises the two steps: (1) the use of edge detection algorithms, such as the Hough transform, to detect the potential edges of the collimator blades in the image, which appear as straight lines; and (2) the selection of desirable edges. Unfortunately, the Hough transform is often unable to detect all the desirable edges because some or all of the collimator blade edges may be too weak for successful detection. As a result, an erroneous area may be selected and the diagnostic quality of image will therefore be compromised.